1. Field of the Invention
The present invention relates to an airbag system comprising: an airbag made of a folded metal plate; and cap members which respectively cap opposite end portions of the airbag, the cap members being fixed to a vehicle body panel, the airbag system protecting a pedestrian by deploying the airbag by use of gas produced by an inflator.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2002-283939 has made publicly known an airbag system for protecting a pedestrian which is configured so that: a folded airbag made of cloth is stored inside a pillar garnish for covering a front surface of a front pillar of an automobile; in collision with a pedestrian, gas produced by an inflator is supplied to the airbag, and thus deploys the airbag along the front surface of the front pillar from a rip which is made when the pillar garnish breaks; and the pedestrian is protected with the airbag thus deployed.
In addition, Japanese Patent Application Laid-open No. 2006-282105 has made publicly known a shock absorbing structure for protecting a pedestrian which is configured so that: a pillar garnish for covering a front surface of a front pillar of an automobile is supported by a pillar skeletal member with a link-type pillar driving mechanism being interposed in between; in collision with a pedestrian, the pillar driving mechanism lifts the pillar garnish up from the pillar skeletal member so as to allow the pillar garnish to make stroke motions; and the pillar garnish thus absorbs the collision energy.
In the case of the invention disclosed in Japanese Patent Application Laid-open No. 2002-283939, however, it is difficult to keep the airbag deployed for a long time because the airbag is made of cloth; therefore, the airbag may not fully exhibit its shock absorbing effects depending on timing at which the pedestrian collides with the front pillar.
In the meantime, the invention disclosed in Japanese Patent Application Laid-open No. 2006-282105 has a problem that: the structure of the link-type pillar driving mechanism for movably supporting the pillar garnish with the pillar skeletal member is complicated; thus, the number of parts increases, and the cost increases.
Against this background, through Japanese Patent Application No. 2009-224381, one of the present assignees has already proposed an airbag system which is configured so that: instead of the conventional airbag made of cloth, an airbag made of metal is folded and arranged in a front pillar; and gas produced by an inflator deploys this airbag toward the outside of a vehicle body.
In the airbag included in this airbag system, opposite end portions of a metal plate folded in the shape of a tube are inserted into respective openings of box-shaped end caps and are fixed thereto by welding. These end caps are fixed to an attachment surface of the front pillar by bolts. Once the folded airbag is deployed, the airbag begins to contract in the longitudinal direction with an increase in the diameter. However, the above-described conventional airbag is incapable of moving in the longitudinal direction because the opposite end portions of the airbag are fixed to the respective end caps. As a result, the tension of the airbag becomes excessive. This makes it difficult for the airbag to be deployed particularly near the end caps thereof, resulting in the possibility of lowering the shock absorbing performance thereof.